Toggle switches

ABSTRACT

A switch including two contact plates spaced in a housing, a bimetallic strip and a stop plate respectively connected to one contact plate, a T-shaped switch handle, a control block mounted around the switch handle, a conductive connecting plate fastened to a neck portion on the switch handle, a cushion mounted around the switch handle a first spring retained between the conductive connecting plate and the cushion, and a second spring supported between the control block and the head of the switch handle, wherein when the switch handle is turned sideways against the stop plate spring, the conductive connecting plate is forced to contact the first and second contact plates, causing the switch switched on; the bimetallic strip is deformed to force the stop plate spring away from switch handle, when the switch is overloaded, causing the switch to trip off.

BACKGROUND OF THE INVENTION

The present invention relates to electric switches, and relates moreparticularly to such electric switches which automatically trip off whenoverloaded.

FIG. 1 shows a toggle switch according to the prior art, which isswitched on when the switch handle is tiled leftwards or rightwards toforce the connecting plate contact one side contact, and which isswitched off when the switch handle is disposed in horizontal. Thisstructure of toggle switch is not easy to assemble. The housing of thetoggle switch is made in integrally. During the assembly process, theconnecting plate must be installed in the housing before theinstallation of other component parts of the switching mechanism.Therefore, the switching mechanism of the toggle switch cannot beassembled into a unit and then fastened to the housing. Another drawbackof this structure of is that the see-saw action of the connecting platetends to cause a contact error if the connecting plate is not preciselyinstalled or when an excessive pressured is applied to the switchhandle. Still another drawback of this structure of a toggle switch isthat it has no overload protection. Furthermore, this structure oftoggle switch is not durable in use.

SUMMARY OF THE INVENTION

The present invention has been accomplished in view of the abovecircumstances. It is one object of the present invention to provide atoggle switch which automatically trips off when overloaded. It isanother object of the present invention to provide a toggle switch whichis easy to assemble. It is still another object of the present inventionto provide a toggle switch which is durable in use.

According to one embodiment of the present invention, the toggle switchcomprises two contact plates spaced in a housing, a bimetallic strip anda stop plate respectively connected to one contact plate, a T-shapedswitch handle, a control block mounted around the switch handle, aconductive connecting plate fastened to a neck portion on the switchhandle, a cushion mounted around the switch handle, a first springretained between the conductive connecting plate and the cushion, and asecond spring supported between the control block and the head of theswitch handle, wherein when the switch handle is turned sideways againstthe stop plate spring, the conductive connecting plate is forced tocontact the first and second contact plates, causing the switch to turnon. The bimetallic strip is deformed to force the stop plate spring awayfrom switch handle, when the switch is overloaded, causing the switch totrip off. Because the conductive connecting plate is forced by springs,it does not displace when disposed in contact with the contact plates.Since the springs, the conductive connecting plate, the cushion, thecontrol block, and the T-shaped switch handle can be assembled into oneunit and then installed in the housing, the assembly process of theswitch is easy.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a toggle switch according to the priorart;

FIG. 2 is an exploded view of a toggle switch according to oneembodiment of the present invention;

FIG. 3 is a schematic drawing, showing the switch handle of the toggleswitch of FIG. 2 shifted;

FIG. 3A is a bottom view in section of the toggle switch of FIG. 2;

FIG. 4 is a side view in section of the toggle switch of FIG. 2;

FIG. 5 is an exploded view of an alternate form of the presentinvention;

FIG. 6 is a sectional elevation of the toggle switch of FIG. 5, showingthe handle stem disposed in the vertical position;

FIG. 6A is a sectional view taken along line 6A--6A of FIG. 6;

FIG. 7 is a sectional elevation of a handle stem shaped like arectangular bar; and

FIG. 7A is a section view taken along the line 7A--7A of FIG. 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 2, 3, 3A, and 4, a toggle switch in accordance withthe present invention is generally comprised of a switch handle 1, aV-shaped control block 2, a cushion 3, a first coil spring 4, aconductive connecting plate 5, a housing 6, a first contact plate 7, asecond contact plate 8, a bimetallic strip 9, a stop plate spring 90,and a second coil spring 10. The switch handle 1 is made ofsubstantially T-shaped configuration having a flat handle stem 11inserted in proper order through a center through hole 21 on theV-shaped control block 2, a center through hole 31 on the cushion 3, thefirst coil spring 4, and a rectangular through hole 51 on the conductiveconnecting plate 5. After the handle stem 11 of the switch handle 1 hasbeen inserted through the rectangular through hole 51 on the conductiveconnecting plate 5, the conductive connecting plate 5 is disposed arounda neck portion 13 on the handle stem 11 and then turned through acertain angle (about 90 degree angle), and therefore the conductiveconnecting plate 5 is fastened to the handle stem 11 to hold theV-shaped control block 2, the cushion 3 and the first coil spring 4 inplace. The second coil spring 10 is retained between the switch handle 1and the V-shaped control block 2 at one side in parallel to the handlestem 11. The switch handle 1 further comprises two opposite pivot pins14 supported in holes in the housing 6 adjacent a transverse groove 22on the V-shaped control block 2 at two opposite sides by the centerthrough hole 21 of the V-shaped control block 2. The first and secondcontact plates 7 and 8 are respectively inserted through two slots 61and 62 on the bottom wall of the housing 6 with the respective contactportion 71 or 81 disposed inside the housing 6. The bimetallic strip 9has one end riveted to a rivet point 710 on the first contact contactplate 7. The stop plate spring 90 has one end fastened to the firstcontact plate 7 at an opposite side relative to the bimetallic strip 9.The stop plate spring 90 is mounted with an adjusting screw 900 foradjusting the sensitivity of the bimetallic strip 9 relative to the stopplate spring 90. The switch handle 1 with the V-shaped control block 2,the cushion 3, the first coil spring 4 and the conductive connectingplate 5 are then inserted into the housing 6 permitting the V-shapedcontrol block 2 to be supported on two opposite steps 63 and 64 on theinside wall of the housing 6. When installed, the contact portion 52 ofthe conductive connecting plate 5 is disposed corresponding to thecontact portions 71 and 81 of the first and second contact plates 7 and8.

Referring to FIG. 3 again, when the switch handle 1 is turned sidewaysto switch on the switch, the handle stem 11 is forced to abut the raisedportion 91 on the free end of the stop plate spring 90, causing thecontact portion 52 of the conductive connecting plate 5 to contact thecontact portions 71 and 81 of the first and second contact plates 7 and8, therefore the switch is switched on. When overloaded, the bimetallicstrip 9 will be deformed to force the adjusting screw 900 downwards,causing the raised portion 91 of the stop plate spring 90 to releasefrom the bottom end of the handle stem 11. When the handle stem 11 isreleased from the constraint of the raised portion 91 of the stop platespring 90, the second coil spring 10 immediately pushes the switchhandle 1 back to its former position, and therefore the switch isswitched off.

FIGS. 5, 6, and 6A show an alternate form of the present invention.According to this alternate form, the control block 2 has a flat bottomsurface 220, which permits the switch handle 1 to be alternatively setin any of three positions. The conductive connecting plate 5 is madesymmetrical. A third contact plate 82 is inserted through an additionalslot 62 on the housing 6 and disposed between the first and secondcontact plates 7 and 8. Two bimetallic strips 9 and two spring plates 90are provided having contact points 820 and rivet points 821 respectivelyconnected to two opposite ends of the third contact plate 82. When theswitch handle 1 is tilted leftwards, the first contact plate 7 and thethird contact plate 82 are electrically connected; when the switchhandle 1 tilted rightwards, the second contact plate 8 and the thirdcontact plate 82 are electrically connected; when the switch handle 1 isdisposed vertical, the third contact plate 82 is electricallydisconnected from the first and second contact plates 7 and 8. If theswitch is overloaded, the respective bimetallic strip 9 will bedeformed, causing the switch handle 1 to trip off.

Referring to FIGS. 7 and 7A, the handle stem 11 is shaped like arectangular bar, and the size of the rectangular through hole 51 on theconductive connecting plate 5 is approximately equal to the crosssection of the handle stem 11. When the handle stem 11 is inserted inproper order through the through hole 21 on the control block 2, thethrough hole 31 on the cushion 3, the first coil spring 4, and therectangular through hole 51 on the conductive connecting plate 5, theconductive connecting plate 5 is turned through certain angle, andtherefore the conductive connecting plate 5 is retained to the neckportion 13 of the handle stem 11.

I claim:
 1. A switch comprising:a housing having a pair of opposing endwalls, a pair of opposing side walls and a bottom wall, two slotsdisposed in said bottom wall, two transverse steps disposed on saidrespective opposing end walls and two aligned holes disposed in saidrespective side walls; a first contact plate and a second contact platerespectively extending out of said housing through said slots, eachcontact plate having a respective top end disposed inside said housing;a bimetallic strip having one end fixed to an upper surface of said topend of said first contact plate; a stop plate spring having one endfixed to a lower surface of said top end of said first contact plate; asubstantially T-shaped switch handle having a head, and a stem extendedfrom said head and suspended in said housing, said head having two pivotpins at two opposite sides thereof pivotally mounted in respective saidaligned holes such that said handle is movable between first and secondpositions, said stem having a neck portion near a bottom end thereof; acontrol block mounted around said stem and supported on said transversesteps, said control block having a transverse groove, which pivotallyreceives said handle; a conductive connecting plate fastened to saidneck portion of said stem; a cushion mounted around said stem; a firstspring retained between said conductive connecting plate and saidcushion; and a second spring supported between said control block andsaid head of said switch handle; wherein when said switch handle ispivoted about said pivot pins from said first position to said secondposition, said handle stem is forced against said stop plate spring andsaid conductive connecting plate contacts said first and second contactplates and, when the switch is overloaded, said bimetallic strip isdeformed to force said stop plate spring away from said handle stem,thereby permitting said switch handle to be forced by said second springback to said first position wherein said conductive connecting plate isforced out of contact with said first and second contact plates.
 2. Aswitch comprising:a housing having a pair of opposing end walls, a pairof opposing side walls and a bottom wall, three slots disposed in saidbottom wall, two transverse steps disposed on said respective opposingend walls and two aligned holes disposed on said respective side walls;first, second and third contact plates respectively extending out ofsaid housing through said slots, each contact plate having a respectivetop end disposed inside said housing, said third contact plate arrangedbetween said first and second contact plates; two bimetallic stripsrespectively having one end fixed to an upper surface of said top end ofsaid third contact plate; two stop plate springs respectively having oneend fixed to a lower surface of said top end of said third contact platebelow said bimetallic strips; a substantially T-shaped switch handlehaving a head, and a stem extended from said head and suspended in saidhousing, said head having two pivot pins at two opposite sides thereofpivotally mounted in respective said aligned holes such that said handleis moveable between first, second and third positions, said stem havinga neck portion near a bottom end thereof; a control block mounted aroundsaid stem and supported on said transverse steps, said control blockhaving a transverse top groove pivotally receiving said handle and afiat bottom surface; a conductive connecting plate fastened to said neckportion of said stem; a cushion mounted around said stem and abuttingsaid fiat bottom surface; a first spring arranged about said stem andbetween said conductive connecting plate and said cushion at oppositesides of said stem; and second and third springs arranged between saidcontrol block and said head of said switch handle; wherein when saidswitch handle is pivoted to said first position, said first and thirdcontact plates are electrically connected by said conductive connectingplate; when said switch handle is pivoted to said second position, saidfirst, second and third contact plates are electrically disconnectedfrom said conductive connecting plate; when said switch handle isshifted to said third position, said second contact plate and said thirdcontact plate are electrically connected; and when the switch isoverloaded, a respective said bimetallic strip is deformed to force arespective said stop plate away from said handle, thereby permittingsaid switch handle to be forced by one of said second and third springsto said second position where said conductive plate is force out ofcontact with said first, second and third contact plates.
 3. A switchcomprising:a housing having a pair of opposing end walls, a pair ofopposing side walls and a bottom wall, two slots disposed in said bottomwall, two transverse steps disposed on said respective opposing endwalls and two aligned holes disposed in said respective side walls; afirst contact plate and a second contact plate respectively extendingout of said housing through said slots, each contact plate having arespective top end disposed inside said housing; in holes in the housing6 adjacent a stop plate spring having one end fixed to a lower surfaceof said top end of said first contact plate; a substantially T-shapedswitch handle having a head, and a stem extended from said head andsuspended in said housing, said head having two pivot pins at twoopposite sides thereof pivotally mounted in respective said alignedholes such that said handle is movable between first and secondpositions, said stem having a neck portion near a bottom end thereof; acontrol block mounted around said stem and supported on said transversesteps, said control block having a transverse groove, which pivotallyreceives said handle; a conductive connecting plate fastened to saidneck portion of said stem; a first spring retained between saidconductive connecting plate and said cushion; and a second springsupported between said control block and said head of said switchhandle; wherein when said handle is in said first position, saidconductive connecting plate is out of contact with said first and secondconductive plates; and when said switch handle is pivoted about saidpivot pins from said first position to said second position, said handlestem is forced against said stop plate spring and said conductiveconnecting plate is forced to contact said first and second contactplates.